Friday, March 23, 2018

Smart Buildings - Picking the right wireless technology is HARD but CRITICAL!!

When you begin to explore the range of smart sensor solutions available for your multi-family properties, you will quickly run into a few compelling applications that will require whole-building sensing—or, nearly so. What do I mean by "whole building sensing"? I am referring to instances such as water leak detection, loud noise, or smoke detection, where large quantities of independently-operating sensors must be distributed in all apartments or in all the hallways or stairways or common spaces of a building. It also includes instances where quantities of interdependent sensors are deployed, such as temperature sensors across an entire building, whose data is stitched together to optimize the on/off operations of a boiler providing heat.Regardless of whether the data is used independently (alert: there's a water leak here), or interdependently (the afternoon sun seems to be heating up the west-facing apartments) - that's a LOT of sensors that need to get their data broadcast out and received. And, that's a lot of walls, ceilings, electrical, and mechanical equipment that are providing interference. Choosing the right building-wide wireless technology can be a make-or-break decision for your building! So let me at least get you started, by familiarizing you with some of the options.

What sensor-networking options are there?

In each instance, the need to reliably collect data from a wide field of deployed sensors across a building will require the creation of a whole-building sensor network. If you read carefully between the lines when talking to sensor solution vendors, you will see that in nearly every case your potential vendor is using one of these wireless technologies:

Your vendor may skip over this part of their offering - but you should know that these different technologies each have their own plusses and minuses, and that there is a very fierce competition going on between them, for market acceptance.

How does one decide between them?

The choice of which technology to deploy for whole-building coverage often hinges on:

The nature of the property itself: its physical design, dimensions, construction materials, and overall radio-wave “friendliness” (compatibility to one or another of the wireless technologies' physical properties)

The availability of logical and easy-to-access hub-placement locations on floors or in hallways and common areas (some solutions require more and closely-spaced routers or repeaters)

The limitations in commercial availability of sensor types that support the different wireless technologies: (for example, many smart thermostats support only WiFi connectivity, whereas many retail store-available smart light switches or leak sensors support only Z-Wave or Zigbee)

The power requirements and needed battery life of the deployed sensors or the availability of nearby electrical outlet service (GSM and WiFi need lots of energy, whereas Zigbee and other 900Mhz are more suitable to long-life battery applications.)

The amount of data being sent, and the frequency of transmission (LoRaWAN is suitable and legally useable only for small packet intermittent use.)

What are some examples of sensors/smart devices that use each of the wireless technologies?

Here are some examples of wireless technologies adopted by different known brands:

LoRa – Lotik, ComcastAnd here's what they look like embedded in actual leak-detection sensors commercially available today :(As part of our Aware sensor initiative, we have collected possibly the most extensive collection ever of all sensors and devices connected with leak detection and control. Feel free to drop into our NYC office if you want to get your hands on more of the products being offered in this area.)

How about you guys? What technology is BuildingLink using, and why?

Firstly, you should know that we really love having the opportunity, challenge, and responsibility of selecting or building the best solutions for all of our 4,300+ luxury multi-family property clients. Over the past year, we have undertaken a broad research initiative, trying out different technologies and seeing which ones can be optimized, and which work best for each application. Our research effort has been so in depth, that I run the risk of ruining any interesting cocktail party discussion if someone accidentally asks me what I think of such-and-such wireless. But, since this is not a cocktail party, I get to provide the tip of an answer:Our initial sensor solutions launched last year for fitness centers, and were based on Xbee, a special version of Zigbee (a 2.4GhZ technology). We have since begun migrating clients to —and starting all new clients on —our own 900Mhz solution, which gives you more range, less interference from other 2.4Ghz technologies (like Wi-Fi), and lower costs (since we are building our own versus licensing it).We have also been building out and testing a few LoRaWAN-based solutions as a second technology, for low-data applications that also require long distance sensor deployments —such as for leak detection, garage parking-spot utilization, and other far-field use cases.

We’ve done extensive tests with all technologies under real in-building conditions. We especially thank those partner clients who have given us access to empty buildings to do comprehensive testing across many floors and in many empty apartments. It's been fun being pre-occupancy technology ghosts, flitting around empty facilities.

What does this have to do with leak detection?

Water leak detection in multi-family buildings is probably the sensor application that has done the most to prompt sensor solution vendors as well as property owners and managers to focus on strategies for whole-building sensor networks. Leak detection can involve staying in communication with hundreds or even thousands of sensors in a building (typically 3-10 per apartment) that are sending real time battery status or leak detection alerts all the time. Many of the sensor locations can be deep within a building’s infrastructure, for example inside a kitchen sink cabinet or in an interior bathroom. The amount of data being sent is small, but the value of getting that data sent when a leak occurs is very great. The four vendors we have found that are tackling whole-building leak detection are using either Zigbee Mesh, or 900MhZ, or LoRaWAN. And yet, there is little data and little historic experience on how well any of these technologies work, for example in blanketing entire prewar buildings constructed with thick plaster or wire lathe, or new 30-story high-rise buildings with their new construction materials and interfering electronics.

Is LoRaWAN the best fit, for “whole building” leak detection solutions?

BuildingLink’s current preferred wireless technology for leak detection is LoRaWan. LoRaWAN works outdoors in line-of-site conditions for 30 miles or more. Inside a building it will typically cover between 3 and 20 floors depending on if they are placed near elevator shafts, or near windows with outside buildings nearby that can bounce the signal, ping-pong style, to cover many floors.It is comforting to know that Comcast is deploying LoRa for in-building networks where they have installed cable boxes, and that a LoRa-like technology called Sigfox is now covering much of Europe. But we have plenty of our own research still to complete, because in-building coverage is very different than line-of-site coverage.

We are still learning and tweaking our solutions with the goal of getting maximum coverage with the fewest LoRa gateways needed. We are also testing four different LoRaWAN gateways, and various sensor antenna and power designs.

As you can imagine, when working with wireless technology that can transmit anywhere between 3 floors and 30 miles, it is important but difficult to quickly ascertain where the “edge” of a specific gateway’s transmission range lies. It might carry 30 feet to the left and right, but be near an elevator shaft and carry 200-300 feet vertically. Does one put one gateway transmitter in the center of a building or one on either end every few floors? The answers depend on the factors described in the “How does one decide…?” paragraph.

In order to help with our clients with a quick way to know what they will need, our labs team has built a line of devices we call EdgeReporterTMdetectors and have bundled them into a solution called “Aware-ER by BuildingLink” (ER= EdgeReporting).The way the system works is that the person looking to map the edges of the wireless ranges of one or more LoRaWAN gateways places the Gateways in different but centralized places in the building or property, and then drops 1-20 EdgeReporter detectors through the properties—on different floors, lines, amenity spaces, naming each one in our app to identify its location. When the EdgeReporter devices are turned on, they seek out all available LoRaWAN gateways, and respond to each gateway with the detector ID and location and with the signal strength from the gateway. All inputs from all the EdgeReporter devices are pulled in and sorted and displayed by gateway location, or by building floor or line, thereby making visible the invisible: showing the edge range of the in-place LoRaWAN gateway. Users can then add, subtract, or move gateways based on this revealing snapshot.

We hope you enjoyed this behind the scenes look at some of the engineering goings on at BuildingLink Labs.